In the filing, Gamco Investors Inc. said it had acquired the shares of Zale earlier this year and was evaluating all of its options regarding Zale’s proposed merger with Signet Jewelers.

Gamco said that, based on information filed by TIG Advisors LLC, it was considering voting against the merger.

TIG, which owns 9.5 percent of Zale, is asking shareholders to vote against the sale of the Irving-based jewelry retailer. TIG believes the proposed sale price is “grossly unfair.” It began publicly soliciting shareholders last week to vote against the acquisition.

Zale is encouraging shareholders to vote for the acquisition, which was announced in February, and to accept the $21-a-share offer from Signet. Zale said Thursday that there are risks to its remaining independent. Voting has started and will end during a shareholder meeting May 29 at Zale’s Irving headquarters.

Zale and TIG Advisors have both presented their cases before the corporate governance firm Institutional Shareholder Services Inc.

The group, which advises shareholders how to vote in corporate matters, is expected to issue a report on the pending acquisition as early as next week. Its opinion will affect how Zale’s institutional shareholders vote.